The standard method of ring rolling teeth of bevel gears with hypoid toothings normally starts with a pretreated blank whose shape outside the region to be deformed by profiled tools already corresponds to the desired finished shape. Prior to the rolling the region to be deformed is heated and then the profiled tool together with at least one synchronously rotating clamping device are positioned to form a closed cavity around the heated region to be deformed of the workpiece. The deformation takes place between two rotating tools and the angled upper tool is advanced along its symmetry line during the rolling.
The tool system for carrying out this method comprises two rotating tools that are inclined relative to each according to the shapes of the bevel gears to be produced. The upper profiled tool is advanced axially in a direction along its symmetry line and the region of the workpiece to be shaped during the rolling process is held in a closed cavity that is formed by the upper profiled tool and at least one synchronously rotating clamping device.
German 3,526,796 describes a method wherein workpieces are produced by advancing the upper tool in the direction of the fixed angle set in the machine of the hole upper tool. Naturally there is no means for adjusting the angle of inclination. The radial limits of the material flow are defined by fixedly connected clamping elements. Synchronization of the tools' rotations is ensured by toothed synchronizers near the tools, the gears being adjusted under load according to the roller advance, a process that obviously is subject to considerable wear.
German 2,611,568 furthermore shows a method of making annular workpieces with highly profiled sections and a roller tool to carry out the method, where two relatively adjustable rollers set at a fixed angle to each other and of which at least one is driven to produce the negative of the profile to be rolled. The angle is fixed by the machine and naturally there is no system for adjusting the angle of inclination. With this so-called axial die rolling there is above all no production of a tangential profiling on the back side of the workpiece and there is naturally no profiling corresponding to the tools as well as clamping device and kinematic coupling of the tools.
German 1,812,423 also describes a machine for rolling or roll-hobbing teeth in bevel gears where the toothed roller tool is fixed on a steppedly advanced spindle that works together with a spindle carrying the workpiece blank and in which one of the spindles is pivoted on a link whose axis is perpendicular to a plane that extends through the spindle axes.